San Antonio, TX Weather
San Antonio hourly forecast: next 24 hours
Today's high of 97°F (36°C) is about 6°F (3°C) above the typical September high of 91°F (33°C).
Current conditions in detail
San Antonio weather tomorrow (Thursday, September 17)
Tomorrow in San Antonio looks overcast, with a high of 92° and an overnight low of 77°. Precipitation chance is modest at 23%. Winds top out near 13 mph, and the UV index reaches 7 (high).
San Antonio 14-day forecast
About the weather in San Antonio
Expect hot, humid summers and generally mild winters in San Antonio: that is what a humid subtropical climate means in practice. Highs peak at 96°F (36°C) in August and fall to 63°F (17°C) by January, with 9.1 hours of sun on an average day.
San Antonio weather: quick facts
- Hottest month: August - highs near 96°F (36°C)
- Coldest month: January - highs near 63°F (17°C)
- Decade extremes (2015-2024): 107°F (42°C) high · 8°F (-13°C) low
- Wettest month: May (16 rainy days) · Sunniest: July (12.0 h sun/day)
- Climate type: humid subtropical
- Annual swing: 18°C between the average warmest and coolest month · day to night: 10°C
- Months averaging 30°C or hotter: 5
- Average humidity: 67%
Temperatures through the year
Warmth peaks in August: highs of 96°F (36°C), lows of 77°F (25°C). January is the coolest month, with highs of 63°F (17°C) and lows near 44°F (7°C). The gridded 2015-2024 daily record for this location tops out at 107°F (42°C) and bottoms at 8°F (-13°C) - decade extremes, not all-time station records. Snowfall is rare but not unheard of.
Rain, sun and snow
Days and nights are about 10°C apart on average - wider than roughly 78% of the cities we track. Four of the twelve months pair mild highs with fewer than twelve wet days; the longest unbroken run is February through March. The wettest month is May (6.8 inches (172 mm) across 16 days) and the driest February. Relative humidity averages 67% across the year, drier than about 75% of the cities we track.
Season by season
Spring (March through May)
Through spring, San Antonio runs hot: 81°F (27°C) by day, 62°F (17°C) after dark, and rain falls on around 38 of the 90 days.
Summer (June through August)
Summer turns very hot here - highs near 95°F (35°C), nights near 76°F (24°C), and expect showers on roughly 25 days across the season. Daylight is generous - around 11.7 hours of sun a day.
Fall (September through November)
Through fall, San Antonio sits firmly in the heat: 82°F (28°C) by day, 64°F (18°C) after dark, and expect showers on roughly 27 days across the season.
Winter (December through February)
Winter in San Antonio stays on the cool side of mild, with daytime highs averaging 66°F (19°C) and nights around 46°F (8°C); expect showers on roughly 24 days across the season.
Average temperatures in San Antonio by month
| Month | High | Low | Rain days | Precipitation | Sunshine | Humidity |
|---|---|---|---|---|---|---|
| January | 63° | 44° | 8 | 2.2 in | 7.4 h/day | 65% |
| February | 67° | 47° | 8 | 2.1 in | 7.0 h/day | 67% |
| March | 76° | 56° | 10 | 2.5 in | 7.8 h/day | 66% |
| April | 81° | 61° | 12 | 4.1 in | 8.8 h/day | 67% |
| May | 86° | 69° | 16 | 6.8 in | 9.6 h/day | 74% |
| June | 93° | 74° | 11 | 2.9 in | 11.6 h/day | 69% |
| July | 96° | 76° | 7 | 2.6 in | 12.0 h/day | 64% |
| August | 96° | 77° | 7 | 3.1 in | 11.6 h/day | 62% |
| September | 91° | 73° | 10 | 4.0 in | 10.3 h/day | 66% |
| October | 83° | 64° | 8 | 3.8 in | 9.2 h/day | 63% |
| November | 71° | 54° | 9 | 2.8 in | 7.0 h/day | 70% |
| December | 66° | 48° | 8 | 2.3 in | 6.7 h/day | 69% |